Tire gauge



atented et. ld, 1924i.

THOMAS C. COOIPER, .0F CHICAGO, ILLINOIS.

TIRE GAUGE.

Application 'ledfNovember 28, 1921. Serial No. 518,129.

To all whom t may concern.:

Be it known th-at I, THOMAS C. Coornn, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tire Gauges, of which the lfollowing is a specification.

This invention relates to improvements in pressure gauges `for pneumatic tires.

One object of the invention is to provide a gauge oi this character which shall be simple in construction and operation, economical to manufacture and one where in the `use of all springs, such as now commonly employed in gauges of this character, may be dispensed with.

Other objects of the invention will be apparent to those skilled in 4:the art from `a read-ing oi the following specification, taken in connection with the accompanying drawings wherein one form of the `invention is illustrated.

`In the drawings- Figure Ilv is a sideelevation o'f a gauge constructed in accordance with the present invention.

Fig. 2 is a longitudinal sectional view.

Fig. 3 is a sectional view vtaken on the line oi Fig. 2.

Fig. 4 is a plan view Vof the `pressure indicating means; and

F ig. -5 is a sectional 'view of an elbow attachment `for use with the gauge `when an air valve is encountered which does not permit oi the gauge being employed in the usual way.

is is well known, the tire gauges now in use embody in their construction an elongated coil spring for counteraoting the ups ward or outward movement of the gauge bar or its equivalent, `and for returning `the latter' to its normal position immediately upon the release of the Vfluid pressure being measured. In other words, these springs in the `gauges lnow on the market form the basis for the 'pressune reading calibrations.'y

The present improvements contemplate the vprovision of a gauge `of the character described, which shall 4operate .on what may be 'termed the dash pot or air cushion principle, 'utilizing the same both as the `:basis for the pressure reading calibrations and for returning the pressure responsive element oit the gauge to its normal position each time the fluid pressureV being measured is released. In this way the use oi all springs mayv be entirely dispensed with.

Referring more in detail to the drawings the gauge is shown as comprising an outer cylindrical barrel or casing ll0, closed at its upper end Vand open at its lower end, and provided `with an elongated longitudinally extended slot `ll in its side wall, said slot extending from the lower open end thereof upwardly and terminating substantially midway of the ends of the casing. The longitudinal edges of this slot may be beveled, iii' desired, as shown in the drawings and at opposite sides of the slot the casing is provided with gr-aduations l2, the

latter being numbered i-n staggered relation from one side of the slot `to the other and beginning at the `bottom of the casing and extending upwardly therefrom to a point adjacent the upper end of the slot.

A suitable deflating element 13 is held lirmly against the lower edge ot the casi-ng l0 by means of a ferrule or thimble 14, which engages tightly over Athe lower end of the casing l() in such wise as to hold the deflating element firmly in position. The deilating element 13 is in the form of a downwardly turned cup 13 which may be of metal or other suitable material, said cup being provided with a downwardly ein tending centrally apertured nipple 13b,

which may be formed integrally 'with the base of `the cup 13a. An annular washer or gasket 13 is litted into the cup, the outer face thereof lying substantially flush with the edges thereof and the lower end of the `nipple as shown more clearly in Fig. 2 of the drawings. The ierrule or thimble 14; is provided with a central opening surrounding which is an inturned vflange 14, the latter engaging against the tace of the rubber washer 13C. The th-iinble` la is also provided with a washer 14h which is preterably ot metal and which also coacts with the rubber washer '13C in sealing the connection between the thimble and the de- Hating element. Carried by `the delating element and extending upwardly therefrom to a point above the upper end of the slot l1 is a post -or other xed element l5 the same carrying at its upper end a suitable or other retaining element 15C.`

extending duct 15d' which registers at its lower end with the duct in vthe-nipple 13b and at its upper endopens above the piston head 15au through a registering duct 'provided in the screw or retaining element 15C. n lMounted within the casing or housing Vis a cylinder 16 open at its lower end 'and closed at its upper end, said cylinder being preferably of substantially less diameter than that of the casing so that the side walls of the cylinder and casing will be spaced a substantial distance apart. Normally the fixed element carrying the piston head 15.@ at its upper end extends upwardly intoA the cylinder 16, to a point in close proximity l f to the upper closed end of said cylinder, as shown in Fig. 2,- the'piston head 15?1 engaging the side walls of said cylinder and serving to seal thespaoe between the said head and the upper end of the cylinder, The cylinder 16 at its upper closed end carries a piston -head 16l which vmaybe of the same construction as piston 15L previously described. f This pistonhead 16a-engages the side walls of the casing 10fabove the .upper end 'of the slot 11 and serves to sealthe space between said head andthe upper closedend of said casing.

The lower end of ,fthe cylinder 16 is liared outwardly as at 16b and normally engages theupp'er surface of the cup 13a'of the del flatingjelement, said element in this way acting as a stop for limitingl the downward movement of the cylinder 16.* A collar 17 surrounds the cylinder 16 above the lower flared end 16b and is disposed intermediate the ywallthereof and the adjacent inner wall ofthe outer casing 10. Thiscollar 17 carries f a plurality of ngers 17a and 17"., the latter engaging the inner `Surface of the wall of the casing 10 at opposite sides of the slot 11 and the former, engaging the outer surface of-said-wall at opposite sides of the slot.y ySuitable retaining means, shown in n theldrawings inthe form of a set screw 17C,

may be `employed for holding thesefingers 17;L land 17b yin pro-per adj-.usted position so that the same will serve to hold the collar 17 inany of its indicating'positions to which it may be moved during the operation of the Oauge as vhereinafter described.,y The outer nger 17av serves v.as the `indicator land is adapted to be read in conjunction with the calibrations or graduations v12'provided Von each side of the slot 11. 'Io'thisl end the finger .17a may besuitably notched at its opposite ends "forreading in conjunction with the vgraduation's on the wall of the casing 10,

or, ifdesired the upper or lower edge of the fingermay be employed for this purpose.

In the use of the gauge, the same is placed over the valve casing of a pneumatic tire, said casing being received within the central opening defined byk the flange 14 of the thimble 14. The gauge -is then pressed firinly down on the valve casing during which operation the nipple 13" engages the upper end of the valve stem and unseats the valve, thereby permitting a portion of the Huid under pressure within the tire `to flow upwardly through the duct 15d and into` the space between the piston head 15CL and the upper closed end of the cylinder 16. This causes the cylinder 16 to be raised until the pressure of the air compressed within the space 18 between the piston head 16u and the upper closed end of the casing 1() connterbalances the Huid pressure being measured or that Within the space between the piston head 15a and the upper closed end of the cylinder 16. The collar 17 together with the indicating finger 17a is raised a distance equal to that through which the Vcylinder 16 is raised owing to the engagement between the collar 17 and the outwardly flared lower end 16b of said cylinder. Immediately upon the removal of the gauge from the valve casing or upon the release of the fluid pressure being measured5 the cylinder 16 is returned to its normal position with its lower end in engagement with the top of the deiating element 13 by the air which was compressed in the spacev 18 during the upward travel of thek cylinder. During this return movement of the cylinder 16, however, the collar 17 and the indicatinr means carried thereby, remains in its indicating position for the fluid pressure just measured, owing to they engagement of the fingers 17 u and 17b with the wall of the outer casing 10, as previously described. When it is desired to take another reading the collar 17 may be returned to its lowermost position andv in engagement with the outwardly flared end 16b by merely grasping the finger 17l and moving the same downwardly. desired, a drop or two of oil may be placed around the edges of the two lea-ther cups of the piston heads 151L and 16u as a further step in sealing the chambers or spaces above said )iston heads and in rendering the same su stantially airtight. Y i

In Fig.l 5 an elbow 19 is shown, the latter` being provided aty one end with a deilating element 20;and a thimble or ferrule 21 both constructed and arranged as the 4corresponding elements of the gauge scribed The other end of the elbow 19 is screw threaded as at 22 and adapted to be screwed into the central opening provided inthe ferrule or thimble 141of the gauge, said opening being correspondingly screw threaded for receiving the same. In this way the gauge may be employed for measuring the air pressure in tires which may be attached previously dei,

to certain types of disk or wire wheels, where access to the air valves would otherwise be so obstructed as to render the use of the gauge, without some such attachment, impossible.

It will bei obvious to those skilled in the art that the present improvements are susceptible yto change and modification, and it is not, therefore, desired to restrict the same except where limitations appear in the appended claims.

l/Vhat I claim is l. In a pressure gauge, a plurality of inter fitting cylinders open at their lower ends and closed at their upper ends, the inner cylinder being longitudinally movable within the outer cylinder and the space between the closed ends of said cylinders being substantially airtight, means for conducting the fluid under press-ure into said inner cylinder to raise the latter, thereby ensmalling said space until the pressure therein and that of said fluid are counterbalanced, and means associated with said inner cylinder for indicating such pressure.

2. In a tire gauge, a cylindrical outer casing opened at one end and closed at the other, a plurality of piston heads within said casing one being stationary and the other movable, the latter being disposed intermediate the former and the closed end of said casing, means for conducting the fiuid under pressure to the space between said pis tons, and means associated with said movable piston for indicating the movements thereof in terms of pressure.

In a tire gauge, a cylindrical casing open at its lower end and closed at its upper end and having a longitudinally extend ing slot in the side wall thereof, a cylinder open at its lower end mounted'within said casing and provided with a piston head at its upper end spaced from the closed end of said casing and engaging the wall of the latter, deiiating means at the open end of said casing, ya fixed element extending upwardly from said means into said cylinder and carrying a piston head at its upper end which engages the side walls of said cylinder, said deflating means, said fixed element and the piston head carried thereby being provided with a common air passage, and pressure indicating means extending through said slot and movable with said cylinder in one direction.

4. In a tire gauge, a cylindrical casing open at its lower end and closed at its upper end and having a longitudinally extending slot in the side wall thereof, a cylinder open at its lower end mounted within said casing and provided with a p-iston head at its upper end spaced from the closed end of said casing and engaging the wall of the latter, deflating means at the lower end of said casing, a fixed element extending upwardly from said means into said cylinder and carrying a piston head at its upper end which engages the side walls of said cylinder, a duct extending through said deflating means, said fixed element and the piston head carried thereby, pressure indicating means visible through said slot and movable With said cylinder in one direction, and means for retaining said last named means in its operative indicating position for each reading independently of said cylinder.

5. In a tire gauge, a cylindrical casing opened at its lower end and closed at its upper end and having a longitudinally extending slot in the side wall thereof, a cylinder open at its lower end mounted within said casing and provided with a piston head at its upper end spaced from the closed end of said casing and engaging the wall of the latter, deflating means at the lower end of said easing, a fixed element extending upwardly from said means into said cylinder and carrying a piston head at its upper end which engages the side walls of said cylinder, a duct extending through said deflating means, said fixed element and the piston head carried thereby, pressure indicating means visible through said slot and movable with said cylinder in one direction, and means for retaining said last named means in its operative indicating position for each reading independently of said cylinder, the air compressed between the piston head of said cylinder and the closed end of said casing during each operation of said gauge serving to return said cylinder to normal position upon the release of the pressure being measured.

In testimony whereof, I have subscribed my name.

THOMAS C. COOPER. 

